Miniature casing pressure operated switch with resilient contact spacer and short circuit prevention structure



p 28, 1965 J. A. WEISSBURG 3,209,039

MINIATURE CASING PRESSURE OPERATED SWITCH WITH RESILIENT CONTACT SPACER AND SHORT CIRCUIT PREVENTION STRUCTURE Filed Aug. 17, 1962 United States Patent.

MINIATURE CASING PRESSURE OPERATED SWITCH WITH RESILIENT CONTACT SPACER AND SHORT CIRCUIT PREVEN- TION STRUCTURE James A. Weissburg, Whitehall Borough, Pa., assignor to The Bryant Electric Company, Bridgeport, Conn., a corporation of Connecticut Filed Aug. 17, 1962, Ser. No. 217,723 2 Claims. (Cl. 20016) The present invention relates to electric switches and more particularly to switches so arranged structurally as readily to be characterizable with miniature size.

In arranging structural elements so as to form a switching device, it is convenient to employ functional analysis as a basis for obtaining an efficient combination. Thus, in assessing the essential functional requirements of a switchfor given applications, the number and complexity of needed structural elements can be reduced as compared to known switch combinations. The present invention is in part the product of a conceptual approach similar to that just described, and it represents an efficient and economical switch which can, if desired, be characterized with relative miniaturization.

According to the broad principles of the invention, a switch comprises a pair of conductive terminals normally held in spaced relation by a resilient insulative spacer or other means and provided with respective contact portions for making and breaking an electric circuit through the terminals. The contact portions can be so arranged on the terminals as to be either normally open or normally closed. A flexible insulative casing is formed closely around the terminals and spacer so that only a circuit connecting portion of each terminal is exposed to the exterior. Operation of the switch is then accomplished simply by pressing the casing to urge the terminals together, with the switch being deactivated when the casing 'is released.

It is, therefore, an object of the invention to provide a novel and efiicient switch.

It is a further object of the invention to provide a novel and efficicnt switch which can be characterized with miniaturized size.

Another object of the invention is to provide a novel and efficient casing operated switch characterized with miniaturized size and wherein the terminals are normally held in closed circuit relation.

These and other objects of the invention will become more apparent upon consideration of the following detailed description along with the attached drawing, in which:

FIGURE 1 is a perspective view of a switch constructed in accordance with the principles of the invention;

FIG. 2 is a perspective view of terminal and spacer parts of the switch of FIG. 1;

FIG. 3 is a view of a cross-section of the switch of FIG. 1 .with the terminals thereof in normally spaced relation to provide an open circuit;

. FIG. 4 is a view similar to that shown in FIG. 3 but differs therefrom in that the terminals are shown as being urged toward each other to provide a closed circuit;

FIG. 5 is a view of a cross-section of another embodiment of the invention in which the terminals normally provide a closed circuit;

FIG. 6 is a view similar to that shown in FIG. 5 but differs therefrom in that the terminals are shown as being urged toward'each other to provide an open circuit;

FIG. 7 is a'partial top plan view of a terminal that can be used as a part of the switch of FIG- 5; and

FIG. 8 is a View of a cross-section of another pressure operated embodiment of the invention in which the terminals normally provide an open circuit.

ICE

As one embodiment of the invention, there is shown in FIG. 1 a switch 10 which comprises an insulative casing 12 through which respective terminal portions 14 and 16 (of any desired wire or conductor connecting form) protrude for establishing respective electrical connections. In this instance, the terminal connecting portions 14 and 16 are formed to fit over respective terminal lugs (not shown). The size of the switch 10 can be at least as little as one-quarter of an inch in diameter. The material used to form the casing is prefer-ably flexible as well as insulative and rubber and some plastics are examples of materials acceptable on this basis.

In constructing the switch 10, a pair of elongated flexible and conductive terminals 13 and 15 (FIG. 2) are assembled together with resilient insulative means or a resilient insulative spacer 18 located therebetween, and the casing 12 is then poured or molded or otherwise suitably formed closely about the terminals 13 and 15 and the spacer 18 so as to support the latter elements in operative relation to each other. When the casing material is formed about the terminals 13 and 15, it is preferred that the material be formed sufficiently closely about the terminals 13 and 15 just inwardly of the terminal connecting portions 14 and 16 so as to seal the interior of the switch against entry of moisture or air. However, if entry of moisture or air is not specified as a limiting environmental condition, then this seal need not be effected. It is not necessary that bonding occur at interface 19 of the spacer 18 and casing 12, but such bonding is tolerable if it occurs.

Each terminal 13 or 15 includes contact means or a contact portion 20 which is located within the casing 12 and which is integrally attached to the terminal connccting portion 14 or 16. The contact portion 20 of each terminal 13 or 15 is in this case circular in geometry, but other shapes can be employed. A conductive relation between the terminals 13 and 15 can be established directly between the terminal contact port-ions 20 or, as here, can be established between the contact portions 20 through respective contact buttons 22 of a suitable conductive material such as silver. The contact buttons 22 can be attached to the terminal contact portions 20 by any well known means such as by riveting.

As can be ascertained from FIGS. 3 and 4, it is preferred that the inner diameter of the spacer 18 be sulficiently large to prevent the flow of the spacer material.

between the contact buttons 22 when the later are pressed into engagement as shown in FIG. 4. The switch 10 is normally open since the contact buttons 22 are normally held in spaced relation by the spacer 18 as shown in FIG. 3, but when the casing 12 is pressed against the terminals 13 and 15 manually or otherwise, the terminal contact portions 20 are actuated toward each other since the resilient insulative spacer 18 is urged under the applied force from its normal static force state to a second or relatively highly compressed static force state.

The contacts 20 then remain engaged with each other until the applied force on the casing 12 is released. When the force is released the inherent resiliency of the spacer 18 forces the terminals 13 and 15 apart and the contact buttons 22 into disengaged relation. The spacer 18 is preferably ring-like in form although other shapes can be employed so long as the return force provided by the spacer 18 is sufliciently distributed to ensure terminal separation.

In FIGS. 5-7, there is shown another embodiment of the invention in the form of a switch 30 having normally closed contact means 32. The switch 30 is substantially similar to the switch 10, but different terminals 34 and 36 are provided therefor. Further, an insulative casing 38 and an insulative resilient spacer 40 therefor are slightly enlarged as compared to the corresponding elements of the switch 10. The terminals 34 and 36 are provided with respective contact fingers 42 and 44 which, for example, can be punched from the plane of respective terminal contact portions.

The contact fingers 42 and 44 are generally L-shaped and are so disposed relative to each other as to have re spective base legs 48 and 50 located opposite each other for engagement of the contact means or contact buttons 32. Each base leg 48 or 50 is further located between the other base leg 50 or 48 and the terminal 36 or 34 to which the base leg 50 or 48 is integrally attached. In this manner, the normal separating force produced by the resilient spacer 40 against the terminals 34 and 36 results in normal engagement of the contacts 32 since the base legs 48 and 50 are urged toward each other.

It follows that the switch 30 is normally closed as previously set forth and, with the application of force to the casing-38, the terminals 34 and 36 are pressed toward each other to compress the spacer 40 and accordingly separate the contacts 32 as shown in FIG. 6. It is preferred that the spacer 40 normally be placed under some compression, as shown in FIG. 5, even in the inactivated state of the switch 30, so as to produce some contact engagement pressure under these circumstances. If desired, additional area of the terminal contact portions 46 can be punched out therefrom as waste material, as indicated by the reference character 52, so as to safeguard against short circuit conditions when the switch 30 is activated to the open condition shown in FIG. 6.

In FIG. 8, a switch 60 is shown as similar to the switch 30 of FIG. 6, but it can also be formed similar to the switch of FIG. 1. The essential difference between the switch 60 and the switches 10 and 30 is that the switch 60 is provided with a casing 62 having a hose or conduit 64 formed as an integral or attachable part thereof. If spacer 65 is provided with flow opening 66 and if the casing 62 is suitably sealed as described in connection with the casing 12 of FIG. 1 and the hose 64 is connected to an intermittent source of pressure (such as air or oil or vacuum), then switch operation is obtained by controlling the pressure within the casing 62 by suitable pressure control means. If the switch 60 is formed as shown, then it is normally open and closes when pressurized internally. If the switch 60 is formed similar to the switch 10, then it is normally closed (as in FIG. 4) and open (FIG. 3) when pressurized internally.

Where desired, the casing 12 or 38 or 62 can be sulficiently elongated to accommodate a plurality of pairs of terminals 15 and 17 or 34 and 36 or combinations of these terminal pairs to form plural switchable circuits in a single device. Further, adhesive material can be provided on at least one side of tape-like or other forms of the invention to provide ready means for firm switch placement.

by relatively simple elements, namely, the terminals 13 I and 15 or the terminals 34 and 36. Further, the casing 12 or 38 (or 62 in some applications) both supports the terminals 13 and 15 or 34 and 36 and serves as an actuator for making and breaking the switch contacts 22 or 32.

The various described embodiments including the switches '10, 30 and are useful in'numerous applications. For, example, the switches 10 and 30 can be incorporated in the fingertips of gloves and in this manner an operators hands are relatively free to performvarious tasks while switch access is maintained. As another example, because of the relatively small mass and elastic nature of the switch 10 or 30 or 60, it is highly resistant to shock, vibration and acceleration forces so as to be suitable for use in aircraft and space vehicles.

In the foregoing description, several embodiments of the invention have been set forth in order to point out the principles of the invention. Accordingly, it is desired that the invention be not limited by the embodiments described, but, rather, that it be accorded an interpretation consistant with the scope and spirit of its broad principles.

What is claimed is:

1. An electric switch comprising a pair of elongated conductive terminal members, an insulative resilient spacer ring member disposed between respective generally circular and parallel portions of said terminal members, respective fingers extending outwardly of said terminal portions and within said ring, respective end portions of said fingers having contact means thereon, each of said finger end portions disposed between the other finger end portion and the terminal portion from which said other finger extends so as to enable said contact means normally to be engaged when said spacer member is free of external force, each of said terminal portions having an opening with the end portion of the finger extending from the opposing terminalportion aligned therewith and movable therethrough so as to safeguard against a short between said terminal portions when said contact means are disengaged, an insulative flexible unitary casing closely surrounding and thereby supporting said members so as to enable said terminal members to be urged toward each other by actuating force on said casing and to be urged apart by the resilient force of said spacer ring member when said actuating force is released, and a circuit connecting portion of each terminal member protruding through said casing.

of said finger end portions disposed between the other finger end portion and the terminal portion from which said other finger extends so as to enable said contact means normally to be engaged when said spacer member is free of external force, each of said terminal portions having an 'op'eningwith the end portion of the finger extending from the opposing terminal portion aligned therewith and movable therethrough so as to safeguard against a short between said terminal portions when said contact means are disengaged, an insulative flexible unitary casing closely surrounding and thereby supporting said members so as to enable said terminal members to be urged toward each other by actuating. force on said casing and to be urged apart by the resilient force of said spacer ring member when said actuating force is released, said casing normally compressing said spacer ring member to a limited extent through said terminal portions so that said contact means are normally engaged under given pressure, and a circuit connecting portion of each terminal member protruding through said casing.

References Cited by the Examiner UNITED STATES PATENTS 1,684,530 9/28 Bast 200-83 2,244,933 6/ 41 Armstrong 200-86 2,367,441 1/45 Schwinn 200-168 X 2,421,149 5/47 Hard Af Segerstad 200-83 X 2,583,813 1/52 Burke 200-86 2,734,969 2/56 Mallory 200-168 X 2,823,279 *2/58 Schulenberg 20086 2,843,694 7/58 Bertaux 200-86 2,909,628 10/59 Cooper 200-86 2,959,647 11/60 Hohmann 200-86 2,975,350 3/61 Mahoney 200-86 X BERNARD A. GILHEANY, Primary Examiner. 

1. AN ELECTRIC SWITCH COMPRISING A PAIR OF ELONGATED CONDUCTIVE TERMINAL MEMBERS, AN INSULATIVE RESILIENT SPACER RING MEMBER DISPOSED BETWEEN RESPECTIVE GENERALLY CIRCULAR AND PARALLEL PORTIONS OF SAID TERMINAL MEMBERS, RESPECTIVE FINGERS EXTENDING OUTWARDLY OF SAID TERMINAL PORTIONS AND WITHIN SAID RING, RESPECTIVE END PORTIONS OF SAID FINGER HAVING CONTACT MEANS THEREON, EACH OF SAID FINGER END PORTIONS DISPOSED BETWEEN THE OTHER FINGER END PORTION AND THE TERMINAL PORTION FROM WHICH SAID OTHER FINGER EXTENDS SO AS TO ENABLE SAID CONTACT MEANS NORMALLY TO BE ENGAGED WHEN SAID SPACER MEMBER IS FREE OF EXTERNAL FORCE, EACH OF SAID TERMINAL PORTIONS HAVING AN OPENING WITH THE END PORTION OF THE FINGER EXTENDING FROM THE OPPOSING TERMINAL PORTION ALIGNED THEREWITH AND MOVABLE THERETHROUGH SO AS TO SAFEGUARD AGAINST A SHORT BETWEEN SAID TERMINAL PORTIONS WHEN SAID CONTACT MEANS ARE DISENGAGED, AN INSULATIVE FLEXIBLE UNITARY CASING CLOSELY SURROUNDING AND THEREBY SUPPORTING SAID MEMBERS SO AS TO ENABLE SAID TERMINAL MEMBES TO BE URGED TOWARD EACH OTHER BY ACTUATING FOREC ON SAID CASING AND TO BE URGED APART BY THE RESILIENT FORCE OF SAID SPACER RING MEMBER WHEN SAID ACTUATING FORCE IS RELEASED, AND A CIRCUIT CONNECTING PORTION OF EACH TERMINAL MEMBER PROTRUDING THROUGH SAID CASING. 